From: Pavel Stehule [mailto:pavel.stehule@gmail.com]
> the cumulated lock statistics maybe doesn't help with debugging - but it
> is very good indicator of database (in production usage) health.
I think it will help both. But I don't think the sampling won't be as helpful as the precise lock statistics
accumulation,because the sampling doesn't give us exactly how effective our improvements to PostgreSQL code are. I
rememberPG developers used LOCK_STATS to see how many (or ratio of) lwlock waits decreased by applying patches.
We can use the cumulated lock stats like:
1. SELECT * FROM pg_session_waits;
2. Run a benchmark.
3. SELECT * FROM pg_session_waits;
4. Calculate the difference between 1 and 3.
Or, reset the wait stats before the benchmark run and just use the stats as-is.
I'd like to know why you thought the cumulated wait stats isn't helpful for debugging.
Regards
Takayuki Tsunakawa
